The winds were tricky, out of the East-Northeast at 8-10 knots, a little gusty. Perfect for training. When the wind blows out of the East, and particularly when the wind favors landing to the North, as it did today, you have to be on your toes to prevent a tricky situation from becoming dangerous.
There are a couple of things that an East wind causes. In the diagram below, pretend that North is to the right -the direction of the aircraft labeled 'Straight out departure'. You enter the pattern in the 45 degree entry point on the diagram and then turn parallel to the runway and fly downwind. With an East wind, that means the wind is off your left wingtip and trying to blow you away from the runway. You compensate by flying at an angle with your nose pointed slightly into the wind. Although you aren't parallel, the wind blows you out as you point your nose into the wind and the result is you fly a straight line.
You'd better fly that straight line CLOSE to the runway because as you turn left onto your base leg, your groundspeed will slow as you fly directly into the wind. The airspeed indicator will show the same speed, but your groundspeed will slow by the amount that the wind is blowing. So, your 60 knot groundspeed will slow to 40 knots if the wind is blowing 20 knots.
The solution is to keep the base leg short, or you'll lose altitude and not be making any progress on your pattern. As you turn to final, the wind is now off your right wingtip and trying to blow you away from centerline. You fly at the opposite crab angle, nose pointed slightly into the wind to compensate and track straight.
The wind was gusty and as we turned final, we encountered not just turbulence but wind shear that caused us to lose 10 knots of airspeed almost instantly. Fortunately, I was flying at 60 knots and the stall speed of the glider is quite a bit less than the 50 knots we were suddenly flying at as we went through the shear. The airspeed indicator bounced around wildly for a second or two, then we passed through it and I managed to touchdown pretty much where I was aiming - a little farther than I wanted but not by too much.
Now, I'm checked out for the coming flying season and I need two more flights to be 'current' and carry passengers. I'll work on getting those next week during training as the weather is pretty iffy this weekend. Regardless, it was great to get back in the air and I'm looking forward to the flying 2011 flying season!
